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Modelling and optimization of remote laser welding galvanized steels using statistical methodologies
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Shi, Yanglin (2016) Modelling and optimization of remote laser welding galvanized steels using statistical methodologies. MSc thesis, University of Warwick.
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Official URL: http://webcat.warwick.ac.uk/record=b3068697~S1
Abstract
This thesis is written under the circumstance of “Remote Laser Welding (RLW) System for Eco & Resilient Automotive Factories” project, of which goals are to configure, integrate, test and validate application of RLW system in automotive assembly line. The goal of this study is to identify the RLW process window and optimal parameters setting for four different material stack-ups in the configuration of lap joint.
One-Factor-at-A-Time method is used to determine the process window in which sound welds, free from visible defects such as spatter, cut-through, burn-through and insufficient weld, are produced. One step further, sound welds are transversely cross-sectioned and geometric profiles (top concavity, interface width, penetration and bottom concavity) are measured and compared to industrial standards. Eventually, it is determined that within power [3, 4] kW, speed [2.5,5.5] m/min, gap [0.15, 0.30] mm, welds fulfilling visual and non-visual requirements could be produced for stack-up of DX56D+Z 1.00 mm plus DX54D+Z 1.00 mm.
Paired mean hypothesis test between stack-up of 0.75 mm DX56D+Z plus 1.00 mm DX54D+Z and stack-up of 0.75 mm DX56D+Z plus 1.80 mm DX56D+Z is performed with the objective of testing whether lower thickness is a significant factor affecting the process. The results reveal insignificance. The process modelling is therefore simplified to focus on the stack-up with greatest lower thickness. Thanks to this result, it significantly reduces the total experimental work.
Response surfaces between process parameters (power, speed and gap) and cross-section geometric profile (top concavity and penetration) are built, based on the data collected from the Box-Behnken Design experiments carried out on the stack-up of 0.75 mm DX54D+Z and 1.8 mm DX56D+Z. Optimization with the purpose of increasing speed (reduced weld time), lowering the power (saved energy) and delivering “right” quality is performed on the four stack-ups. It is concluded that: for stack-up of 0.75 mm DX56D+Z plus 1.8 mm DX 54D+Z, the optimal results are speed at 3.30 m/min, power at 3.80 kW, and gap at 0.15 mm; for stack-up of 0.75 mm DX56D+Z sheet plus 1.00 mm DX52D+Z or 1.00 mm DX 54D+Z, optimal results are: speed at 3.86 m/min, power at 3.19 kW, and gap at 0.18 mm; for stack-up 0.75 mm DX56D+Z plus 0.70 mm DX53D+Z, optimal results are: speed at 4.65 m/min, power at 3.20 kW, and gap at 0.15 mm.
Key words: RLW, Galvanized steel, Hypothesis testing, BBD, RSM, Modelling and
Optimization
Item Type: | Thesis (MSc) | ||||
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Subjects: | T Technology > TJ Mechanical engineering and machinery T Technology > TL Motor vehicles. Aeronautics. Astronautics |
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Library of Congress Subject Headings (LCSH): | Laser welding., Steel, Galvanized., Structural analysis (Engineering)., Nondestructive testing -- Technological innovations., Remote sensing -- Mathematical models. | ||||
Official Date: | April 2016 | ||||
Dates: |
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Institution: | University of Warwick | ||||
Theses Department: | Warwick Manufacturing Group | ||||
Thesis Type: | MSc | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Barnes, Stuart,1971-| | ||||
Extent: | xii, 183 pages :illustrations. | ||||
Language: | eng |
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